test2306: make it use a persistent connection

+ enable verbose already from the start

Closes #11621

tests/data/test2306

@@ -17,7 +17,6 @@ Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT
 ETag: "21025-dc7-39462498"
 Accept-Ranges: bytes
 Content-Length: 6
-Connection: close
 Content-Type: text/html
 Funny-head: yesyes
 

tests/libtest/lib2306.c

@@ -39,11 +39,11 @@ int test(char *URL)
 
   cl = curl_easy_init();
   curl_easy_setopt(cl, CURLOPT_URL, URL);
+  curl_easy_setopt(cl, CURLOPT_VERBOSE, 1L);
   curl_easy_perform(cl);
 
   /* re-use handle, do a second transfer */
   curl_easy_setopt(cl, CURLOPT_URL, URL2);
-  curl_easy_setopt(cl, CURLOPT_VERBOSE, 1L);
   curl_easy_perform(cl);
   curl_easy_cleanup(cl);
   curl_global_cleanup();